Entertainment content publishers generally sell content on an individual basis (e.g., one song at a time or a few movies at a time). Traditionally, this content is sold in a brick-and-mortar store, with the content on a storage medium such as a CD or DVD. Recently, however, content publishers have begun to distribute content through online sources and some publishers have even created their own content delivery systems. For example, some artists are now marketing music online and are airing television ads to publicize new album releases. These content delivery changes have been created out of a desire to control delivery and distribution of content, including preventing unauthorized copying.